Clausing Colchester lathe overheating?

[Defender92]

Sorry, another question. I was playing with my Clausing Colchester 13” lathe tonight. I was just practicing turning, facing and threading for about 30 minutes at around 500-700 rpm.

After running it in low speeds for a while I went through the gears just to watch it run at top speed for a moment. And then it shut off. The start light wasn’t lit and it wouldn’t start back up. I checked the breaker in my sub panel and it wasn’t tripped. Turned the breaker off and on and nothing.

Then suddenly it started working again but stopped after a minute. Then after waiting it would power on. I opened the power box and it was pretty hot. Not extremely hot but pretty hot. Mostly the circled electrical piece in the photo. I’m not sure if this is the cause, what’s this is or what’s actually happening. Just guessing it’s overheating???



Can anybody tell me what’s going on with my lathe??? It’s a 3 phase running on a phase-o-matic 4-8hp. 50 amp breaker with the proper gauge wire.

I let it completely cool for about an hour and it was working just fine in low and high speeds. But I didn’t run it long to get hot again.

 

[graham-xrf]

The Klockner Moeller item is a 3-phase contactor. It has now been replaced by DIL0M/22, which is essentially the same thing in function.
Things that can get hot in there are the pull-in coil solenoid, or the contacts, and it helps to try and find out which it is.

The solenoid coil.
This part is powered to hold the contacts in the whole time the motor is running. It drops out when you press OFF button, or the E-Stop. It would get hot if there is a unwanted short-circuit between any coil windings. Short circuit windings heat up really quickly, but usually, if there is a short, the contactor would have trouble actually pulling in.
Heating of the solenoid coil is not related to a spell of running at higher speeds.

The contacts
These have a hard life. They get pitted and burned by the spark splat that happens when they dis-engage, when running current into inductive loads like motors. The usual arrangement is the switch arm blades have a contact at both ends, so that when it moves away, two contacts open. Sometimes one side can get welded on, and stick. In any case, burned up contacts present a resistance that just gets hot, and is related to running at higher speeds. The geared-up drive train loads the motor more. You might get somewhere by cleaning them up with a fine file, but once the plating gets burned, the life is short.

Secondary reason.
You might have something wrong with the motor, causing it to run currents above the contactor rating. Three phase motors are made of fundamental stuff. Steel, copper, and insulation. There is not much that can go wrong with them unless they start having to pull a binding load, or the bearings fail.

The fix.
Once you know for sure the contactor has a problem, you can simply replace it. Given that it is hanging on a DIN rail, it should simply unclip with the help of a screwdriver blade in the latch. Also, you could replace with any other brand you please, that has the correct rating for the contacts, and the solenoid operating voltage. Take care. Many contactors use a safer 24V AC coil for the buttons and E-stops, provided by a transformer in there somewhere. These contactors are not expensive.

Everything I have said above is from an extrapolated bit of guessing. You need to get a bit nosey about poking around with the bits, including disconnecting and removing the contactor to inspect. Take pictures. Label the wires so you can put it together again. This sort of thing can be damn expensive to fix if you call in a professional. Fixing it yourself, with some help from folk at HM is entirely possible, even if you are not particularly into electrics. I expect the full circuit diagram for the Clausing/Colchester kit can be had from someone here.

BTW - is that your pal labrador disapproving of the smell of burning?

 

[sdelivery]

First I believe this is a two speed motor..
Not sure but As I remember a star/delta configuration.
Look at your schematic, better yet post it.
IF it's the two speed system there should be three contactors involved, low ,high and bridge/ brake.
Step one . Find schematic
Step two. Verify voltage to machine.
Step three. Inspect wiring to motor, contactors and thermal protection.
While inspecting gently tighten each terminal screw.
Step four, while running test current in high range as well as low range.
Verify the thermal overload is set for the correct range.
I have seen thermal overload that reset automatically BUT the machine is generally wired to fail safe and not to restart.
I think you will find the bridge/ brake contractor's contacts to need dressing.
Just remove high spots and flash or burrs.

 

[markba633csi]

First thing to check would be the transformer taps- are they set properly for the mains voltage you are using?
The contactor in question has a 115v coil- it may be overheating from too high a voltage or it could be failing internally
-M

 

[FOMOGO]

All good advice above. I've generally found it to be the contactor points to be the issue. Not to big a deal to disassemble and clean/file them. Just pay attention to the way it comes apart. Your phone camera is a big help here. As said not a super expensive part, if the coil is bad or points are fried beyond repair. Mike

 

[Defender92]

Thanks guys! I’m going to try and tinker with it later today. I’m happy it’s probably a easy / cheap fix. I was pretty bummed out last night.

I didn’t notice any burning smell. But the times when it stopped on me the red light stayed on the phase converter before it quit. When it was cooled down and operated fine the light on the phase converter came on briefly and then off while the lathe continued to operate.

Here is some photos of a wiring diagram that was inside the electrical box of my lathe. However it says it’s for a Master 2500 electro-magnetic brake.



And its in a difficult spot to photograph but here’s a shot of the bars my electrical components sit on.



Edit:
After google searching Colchester Master 2500 lathe it looks like that is what I have? I always thought it was a Colchester 8000 series.

 

[markba633csi]

What source of 3-phase power are you using? Rotary or static?
The transformer in your lathe is connected to incoming legs L1 and L2- those should be the "natural" 220v legs
The synthetic leg should be L3
-M

 

[mksj]

In addition to above, with the power off check the wire connection and screw terminals that nothing is loose. If using an RPC, check which leg is the generated wild leg and that should be connected to L3 on the lathe end (i.e. the terminal that do not feed the transformer) input. It also could be increased resistance in the motor contactor.

 

[tq60]

With a static converter you loose a third of your motor power.

Gear head lathe in higher speeds pull more from the motor as oil sloshing in gearbox consumes power.

The contacts in the contactor could not be optimum resulting in a tiny resistance.

Any place electricity flows through any resistance it results in voltage drop.

This can be used to determine the amount of heat generated.

If you can get to the contacts you can burnish them with paper.

Is the oil in the headstock orrect amount and viscosity?

Our 7.5 HP L&S has static converter and it will trip the protector on higher speeds when cold.

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